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Journal Details
Format
Journal
eISSN
2083-4608
First Published
26 Feb 2008
Publication timeframe
4 times per year
Languages
English

Search

Volume 30 (2014): Issue 1 (June 2014)

Journal Details
Format
Journal
eISSN
2083-4608
First Published
26 Feb 2008
Publication timeframe
4 times per year
Languages
English

Search

7 Articles
Open Access

The Analysis Of Synchronous Blade Vibration Using Linear Sine Fitting

Published Online: 03 Jun 2015
Page range: 5 - 19

Abstract

Abstract

In Blade Tip Timing several sensors installed circumferentially in the casing are used to record times of arrival (TOA) and observe deflections of blade tips. This paper aims to demonstrate methodology of model-based processing of aliased data. It focuses on the blade vibration excited by the forces synchronous with engine rotation, which are called integral responses. The driven harmonic oscillator with single degree of freedom (SDOF) is used to analyse blade vibration measured by tip-timing sensors during engine deceleration. When integral engine order EO is known, the linear sine fitting techniques can be used to process data from sensors to estimate amplitude, phase and frequency of blade vibration in each rotation. The oscillator model is implemented in MATLAB and used to generate resonance curves and simulate blade responses observed with tip sensors, installed in the axial compressor. Generated TOA data are fitted to the sine function to estimate vibration parameters. The validated procedure is then employed to analyze real test data.

Keywords

  • turbomachinery
  • blade vibration
  • tip-timing
  • sine fitting
  • least squares
  • harmonic oscillator

Słowa kluczowe

  • przepływowe maszyny wirnikowe
  • drgania łopatek
  • metoda dyskretno-fazowa
  • dopasowanie funkcji sinus
  • metoda najmniejszych kwadratów
  • oscylator harmoniczny
Open Access

Standard Sine Fitting Algorithms Applied To Blade Tip Timing Data

Published Online: 03 Jun 2015
Page range: 21 - 30

Abstract

Abstract

Blade Tip Timing (BTT) is a non-intrusive method to measure blade vibration in turbomachinery. Time of Arrival (TOA) is recorded when a blade is passing a stationary sensor. The measurement data, in form of undersampled (aliased) tip-deflection signal, are difficult to analyze with standard signal processing methods like digital filters or Fourier Transform. Several indirect methods are applied to process TOA sequences, such as reconstruction of aliased spectrum and Least-Squares Fitting to harmonic oscillator model. We used standard sine fitting algorithms provided by IEEE-STD-1057 to estimate blade vibration parameters. Blade-tip displacement was simulated in time domain using SDOF model, sampled by stationary sensors and then processed by the sinefit.m toolkit. We evaluated several configurations of different sensor placement, noise level and number of data. Results of the linear sine fitting, performed with the frequency known a priori, were compared with the non-linear ones. Some of non-linear iterations were not convergent. The algorithms and testing results are aimed to be used in analysis of asynchronous blade vibration.

Keywords

  • turbomachinery
  • blade vibration
  • tip-timing
  • sine fitting
  • least squares
  • harmonic oscillator

Słowa kluczowe

  • przepływowe maszyny wirnikowe
  • drgania łopatek
  • metoda dyskretno-fazowa
  • dopasowanie funkcji sinus
  • metoda najmniejszych kwadratów
  • oscylator harmoniczny
Open Access

A Method For Determination And Standardization Of Performance Parameters For Aircrafts With Electric Drives

Published Online: 03 Jun 2015
Page range: 31 - 46

Abstract

Abstract

The study outlines the technique for flight tests carried out for a plane powered by an electric drive and the method for standardization of performance parameters applicable to evaluation of test results. Due to the relatively new type of drive, which is an electric motor, the literature references provide no descriptions of such issues. Therefore the solutions presented in the paper are the own contribution of the research team from Air Force Institute of Technology (ITWL).

Keywords

  • flight tests
  • standardization method

Słowa kluczowe

  • próby w locie
  • standaryzacja wyników badań
Open Access

The Model Of One-Type Aircraft Fleet Behaviour While Service And Advantages SHM V. NDT Implementation

Published Online: 03 Jun 2015
Page range: 47 - 58

Abstract

Abstract

The paper defines the essence of durability characteristics of the designing structure of an airframe in terms of flight safety. Particular attention is drawn to one of the main factors influencing the durability characteristics of the airframe – diagnostics system for the health assessment of the airframe during the process of operation. The effectiveness of the use of integrated solutions to the structure of the airframe providing a continuous assessment of the technical condition is presented. Continuous diagnostics system integrated with the airframe, SHM, is classified as an intelligent solution. This paper presents a model of the behavior of one-type aircraft operating in the air operator’s fleet in terms of susceptibility to failure. Justified assumption in the description of this behavior, in the form of a “bathtub curve”. The analysis is supported by real data of failures. The benefits of using a continuous diagnostics system integrated with the airframe, SHM, is interpreted in relation to the classical approach with the use of non-destructive testing, NDT, for the three phases of the bathtub curve.

Keywords

  • civil aviation system
  • the air operator
  • airframe
  • durability
  • smart technology in health assessment
  • intensity of failures
  • diagnostics
  • NDT
  • SHM

Słowa kluczowe

  • płatowiec
  • intensywność uszkodzeń modelowa
  • intensywność uszkodzeń rzeczywista
  • diagnostyka
  • NDT
  • SHM
Open Access

Issues Related To Troubleshooting Of Avionic Hydraulic Units

Published Online: 03 Jun 2015
Page range: 59 - 73

Abstract

Abstract

The paper outlines workflows associated with troubleshooting of avionic hydraulic systems with detailed description of the troubleshooting algorithm and classification of diagnostic signals provided by avionic hydraulic systems and their subassemblies. Attention is paid to measurement sequences for diagnostic signals from hydraulic systems, circuits and units. Detailed description is dedicated to an innovative design of a troubleshooting device intended for direct measurements of internal leaks from avionic hydraulic units. Advantages of the proposed measurement method are summarized with benefits from use of the presented device and compared against the methods that are currently in use. Subsequent phases of the troubleshooting process are described with examples of measurement results that have been acquired from subassemblies of hydraulic systems of SU-22 aircrafts currently in service at Polish Air Forces with consideration given to cases when the permissible threshold of diagnostic signals were exceeded. Finally, all results from investigations are subjected to thorough analysis.

Keywords

  • avionic hydraulic unit
  • avionic hydraulic system (LIH)
  • intensity of internal leaks

Słowa kluczowe

  • lotniczy zespół hydrauliczny
  • LIH – lotnicza instalacja hydrauliczna
  • natężenie przecieku wewnętrznego
Open Access

The Attempt To Assess The Technical Condition Of A Gas Turbine Blade When Information On Its Operating Condition Is Limited

Published Online: 03 Jun 2015
Page range: 75 - 86

Abstract

Abstract

The paper discloses a non-invasive method of visual inspection based on processing of images taken for blade surfaces in the spectrum of visible light and then analyzed with the use of a computer-aided technology. The method of computer-aided analysis of images for blade surfaces is presented in details along with the obtained outcome, whilst the results from metallographic investigation of the blade superalloy are disclosed as well. The comparison is made between the results obtained from the analysis of images for blade surface and the results from the metallographic investigation of their structures. Finally, the relationship is established between parameters of digital images taken for surfaces of gas turbine blades in the visible spectrum of electromagnetic waves and microstructural parameters of the turbine blade metal. The completed investigations and analyses reveal that troubleshooting of gas turbine blades, which employs digital processing of images taken for its surface, offers new opportunities to determine the condition of blades after a long-term impact of a working agent at high temperature.

Keywords

  • gas turbine
  • blade
  • diagnosis blades

Słowa kluczowe

  • turbina gazowa
  • łopatka turbiny
  • diagnozowanie łopatek
Open Access

Selected Aircraft Throttle Controller With Support Of Fuzzy Expert Inference System

Published Online: 03 Jun 2015
Page range: 87 - 97

Abstract

Abstract

The paper describes Zlin 143Lsi aircraft engine work parameters control support method – hourly fuel flow as a main factor under consideration. The method concerns project of aircraft throttle control support system with use of fuzzy logic (fuzzy inference). The primary purpose of the system is aircraft performance optimization, reducing flight cost at the same time and support proper aircraft engine maintenance. Matlab Software and Fuzzy Logic Toolbox were used in the project. Work of the system is presented with use of twenty test samples, five of them are presented graphically. In addition, system control surface, included in the paper, supports system all work range analysis.

Keywords

  • throttle controller
  • fuzzy logic
  • fuzzy expert inference system
  • support of control

Słowa kluczowe

  • dźwignia sterowania silnikiem
  • logika rozmyta
  • rozmyty
  • ekspercki system wnioskowania
  • wspomaganie sterowania
7 Articles
Open Access

The Analysis Of Synchronous Blade Vibration Using Linear Sine Fitting

Published Online: 03 Jun 2015
Page range: 5 - 19

Abstract

Abstract

In Blade Tip Timing several sensors installed circumferentially in the casing are used to record times of arrival (TOA) and observe deflections of blade tips. This paper aims to demonstrate methodology of model-based processing of aliased data. It focuses on the blade vibration excited by the forces synchronous with engine rotation, which are called integral responses. The driven harmonic oscillator with single degree of freedom (SDOF) is used to analyse blade vibration measured by tip-timing sensors during engine deceleration. When integral engine order EO is known, the linear sine fitting techniques can be used to process data from sensors to estimate amplitude, phase and frequency of blade vibration in each rotation. The oscillator model is implemented in MATLAB and used to generate resonance curves and simulate blade responses observed with tip sensors, installed in the axial compressor. Generated TOA data are fitted to the sine function to estimate vibration parameters. The validated procedure is then employed to analyze real test data.

Keywords

  • turbomachinery
  • blade vibration
  • tip-timing
  • sine fitting
  • least squares
  • harmonic oscillator

Słowa kluczowe

  • przepływowe maszyny wirnikowe
  • drgania łopatek
  • metoda dyskretno-fazowa
  • dopasowanie funkcji sinus
  • metoda najmniejszych kwadratów
  • oscylator harmoniczny
Open Access

Standard Sine Fitting Algorithms Applied To Blade Tip Timing Data

Published Online: 03 Jun 2015
Page range: 21 - 30

Abstract

Abstract

Blade Tip Timing (BTT) is a non-intrusive method to measure blade vibration in turbomachinery. Time of Arrival (TOA) is recorded when a blade is passing a stationary sensor. The measurement data, in form of undersampled (aliased) tip-deflection signal, are difficult to analyze with standard signal processing methods like digital filters or Fourier Transform. Several indirect methods are applied to process TOA sequences, such as reconstruction of aliased spectrum and Least-Squares Fitting to harmonic oscillator model. We used standard sine fitting algorithms provided by IEEE-STD-1057 to estimate blade vibration parameters. Blade-tip displacement was simulated in time domain using SDOF model, sampled by stationary sensors and then processed by the sinefit.m toolkit. We evaluated several configurations of different sensor placement, noise level and number of data. Results of the linear sine fitting, performed with the frequency known a priori, were compared with the non-linear ones. Some of non-linear iterations were not convergent. The algorithms and testing results are aimed to be used in analysis of asynchronous blade vibration.

Keywords

  • turbomachinery
  • blade vibration
  • tip-timing
  • sine fitting
  • least squares
  • harmonic oscillator

Słowa kluczowe

  • przepływowe maszyny wirnikowe
  • drgania łopatek
  • metoda dyskretno-fazowa
  • dopasowanie funkcji sinus
  • metoda najmniejszych kwadratów
  • oscylator harmoniczny
Open Access

A Method For Determination And Standardization Of Performance Parameters For Aircrafts With Electric Drives

Published Online: 03 Jun 2015
Page range: 31 - 46

Abstract

Abstract

The study outlines the technique for flight tests carried out for a plane powered by an electric drive and the method for standardization of performance parameters applicable to evaluation of test results. Due to the relatively new type of drive, which is an electric motor, the literature references provide no descriptions of such issues. Therefore the solutions presented in the paper are the own contribution of the research team from Air Force Institute of Technology (ITWL).

Keywords

  • flight tests
  • standardization method

Słowa kluczowe

  • próby w locie
  • standaryzacja wyników badań
Open Access

The Model Of One-Type Aircraft Fleet Behaviour While Service And Advantages SHM V. NDT Implementation

Published Online: 03 Jun 2015
Page range: 47 - 58

Abstract

Abstract

The paper defines the essence of durability characteristics of the designing structure of an airframe in terms of flight safety. Particular attention is drawn to one of the main factors influencing the durability characteristics of the airframe – diagnostics system for the health assessment of the airframe during the process of operation. The effectiveness of the use of integrated solutions to the structure of the airframe providing a continuous assessment of the technical condition is presented. Continuous diagnostics system integrated with the airframe, SHM, is classified as an intelligent solution. This paper presents a model of the behavior of one-type aircraft operating in the air operator’s fleet in terms of susceptibility to failure. Justified assumption in the description of this behavior, in the form of a “bathtub curve”. The analysis is supported by real data of failures. The benefits of using a continuous diagnostics system integrated with the airframe, SHM, is interpreted in relation to the classical approach with the use of non-destructive testing, NDT, for the three phases of the bathtub curve.

Keywords

  • civil aviation system
  • the air operator
  • airframe
  • durability
  • smart technology in health assessment
  • intensity of failures
  • diagnostics
  • NDT
  • SHM

Słowa kluczowe

  • płatowiec
  • intensywność uszkodzeń modelowa
  • intensywność uszkodzeń rzeczywista
  • diagnostyka
  • NDT
  • SHM
Open Access

Issues Related To Troubleshooting Of Avionic Hydraulic Units

Published Online: 03 Jun 2015
Page range: 59 - 73

Abstract

Abstract

The paper outlines workflows associated with troubleshooting of avionic hydraulic systems with detailed description of the troubleshooting algorithm and classification of diagnostic signals provided by avionic hydraulic systems and their subassemblies. Attention is paid to measurement sequences for diagnostic signals from hydraulic systems, circuits and units. Detailed description is dedicated to an innovative design of a troubleshooting device intended for direct measurements of internal leaks from avionic hydraulic units. Advantages of the proposed measurement method are summarized with benefits from use of the presented device and compared against the methods that are currently in use. Subsequent phases of the troubleshooting process are described with examples of measurement results that have been acquired from subassemblies of hydraulic systems of SU-22 aircrafts currently in service at Polish Air Forces with consideration given to cases when the permissible threshold of diagnostic signals were exceeded. Finally, all results from investigations are subjected to thorough analysis.

Keywords

  • avionic hydraulic unit
  • avionic hydraulic system (LIH)
  • intensity of internal leaks

Słowa kluczowe

  • lotniczy zespół hydrauliczny
  • LIH – lotnicza instalacja hydrauliczna
  • natężenie przecieku wewnętrznego
Open Access

The Attempt To Assess The Technical Condition Of A Gas Turbine Blade When Information On Its Operating Condition Is Limited

Published Online: 03 Jun 2015
Page range: 75 - 86

Abstract

Abstract

The paper discloses a non-invasive method of visual inspection based on processing of images taken for blade surfaces in the spectrum of visible light and then analyzed with the use of a computer-aided technology. The method of computer-aided analysis of images for blade surfaces is presented in details along with the obtained outcome, whilst the results from metallographic investigation of the blade superalloy are disclosed as well. The comparison is made between the results obtained from the analysis of images for blade surface and the results from the metallographic investigation of their structures. Finally, the relationship is established between parameters of digital images taken for surfaces of gas turbine blades in the visible spectrum of electromagnetic waves and microstructural parameters of the turbine blade metal. The completed investigations and analyses reveal that troubleshooting of gas turbine blades, which employs digital processing of images taken for its surface, offers new opportunities to determine the condition of blades after a long-term impact of a working agent at high temperature.

Keywords

  • gas turbine
  • blade
  • diagnosis blades

Słowa kluczowe

  • turbina gazowa
  • łopatka turbiny
  • diagnozowanie łopatek
Open Access

Selected Aircraft Throttle Controller With Support Of Fuzzy Expert Inference System

Published Online: 03 Jun 2015
Page range: 87 - 97

Abstract

Abstract

The paper describes Zlin 143Lsi aircraft engine work parameters control support method – hourly fuel flow as a main factor under consideration. The method concerns project of aircraft throttle control support system with use of fuzzy logic (fuzzy inference). The primary purpose of the system is aircraft performance optimization, reducing flight cost at the same time and support proper aircraft engine maintenance. Matlab Software and Fuzzy Logic Toolbox were used in the project. Work of the system is presented with use of twenty test samples, five of them are presented graphically. In addition, system control surface, included in the paper, supports system all work range analysis.

Keywords

  • throttle controller
  • fuzzy logic
  • fuzzy expert inference system
  • support of control

Słowa kluczowe

  • dźwignia sterowania silnikiem
  • logika rozmyta
  • rozmyty
  • ekspercki system wnioskowania
  • wspomaganie sterowania

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